chore(python): fix typo in README#306

vchudnov-g merged 3 commits intomaingoogleapis/python-dns:mainfrom

owl-bot-update-lock-631b4a35a4f9dd5e97740a97c4c117646eb85b35e103844dc49d152bd18694cdgoogleapis/python-dns:owl-bot-update-lock-631b4a35a4f9dd5e97740a97c4c117646eb85b35e103844dc49d152bd18694cdCopy head branch name to clipboard